The present invention relates to methods and systems for improving procedures that address cataracts, opacifications in the lens, clear lens extraction, removal of natural lens material, use of lens replacement materials and combinations of these. The present invention additionally relates to systems and methods that provide predetermined, precise and reproducible laser shot patterns for creating incisions in the natural human crystalline lens that are reproducible from patient-to-patient and surgeon-to-surgeon.
In general, presbyopia is the loss of accommodative amplitude. In general, cataracts are areas of opacification within the crystalline lens, which are sufficient to interfere with vision. Other conditions, for which the present invention is directed, include but are not limited to the opacification of the crystalline lens.
Presbyopia most often presents as a near vision deficiency, the inability to read small print, especially in dim lighting after about 40-45 years of age. Presbyopia, or the loss of accommodative amplitude with age, relates to the eyes inability to change the shape of the natural crystalline lens, which allows a person to change focus between far and near, and occurs in essentially 100% of the population over age 45. Accommodative amplitude has been shown to decline with age steadily through the fifth decade of life.
Cataracts, or the condition when the natural crystalline lens becomes opaque and clouds vision, occurs in millions of people per year and are treated effectively with surgical techniques, such as ultrasonic phacoemulsification pioneered by Kelman about 40 years ago. Although the techniques have been refined over the years, safety concerns from ocular trauma, especially to the corneal endothelium from the ultrasonic energy required to break up a hardened cataract is undesirable, especially for those with a compromised corneal endothelium, such as those with Fuchs Dystrophy.
Several difficulties arise in the use of lasers in the treatment of cataracts. Cataracts scatter light, including laser light, and thus can prevent a laser treatment beam from having the desired effect on the tissue being treated. Moreover, the light scattering effect of cataracts and other opacifications can make determining the position and shape of the lens by optical means difficult.
The established treatment for cataracts is the removal of the opacified human crystalline lens and its replacement with an intra ocular lens (IOL). In general, IOLs consist of a small plastic lens with plastic side struts, called haptics, to hold the lens in place within the capsular bag inside the eye. Exemplary types of IOLs include monofocal lenses, multifocal IOLs, which provide the patient with multiple-focused vision at far and reading distances, and accommodative IOLs, which provide the patient with visual accommodation. The flexible nature of many IOLs enables them to be rolled and/or folded up for insertion into the capsule. Examples of IOLs are found in U.S. Pat. Nos. 7,188,949, 6,849,091, 5,699,142 and 5,607,472, the entire disclosures of each of which are incorporated herein by reference. Commercially available IOLs that, by way of example, may benefit from the present invention are CRYSTALENS and ACRYSOF RESTOR.
The CRYSTALENS IOL was developed by Eyeonics and is presently provided by Bausch & Lomb. It is at least in part believed to be disclosed in U.S. Pat. No. 6,849,091. Further information regarding its structure and efficacy is provided by the Food and Drug Administration (FDA) PMA P030002 and related documents to that PMA file. The FDA approved indicated use for CRYSTALENS was in part: “The Crystalens™ Model AT-45 Accommodating IOL is intended for primary implantation in the capsular bag of the eye for visual correction of aphakia in adult patients in whom a cataractous lens has been removed and is intended to provide near, intermediate, and distance vision without spectacles. The Crystalens™ IOL provides approximately one diopter of monocular accommodation.” (Nov. 14, 2003 PMA P030002 at Part 2, Summary of Safety and Effectiveness Data, ¶INDICATIONS FOR USE).
Thus, the CRYSTALENS is an example of an FDA approved accommodating IOL. The term “FDA approved accommodating IOL” refers to any IOL that has obtained FDA approval having an indicated use that provides for accommodation, regardless whether such IOL is actually being employed for such an approved use.
The ACRYSOF RESTOR IOL is provided by Alcon and is at least in part believed to be disclosed in U.S. Pat. No. 5,669,142. Further information regarding its structure and efficacy is provided by FDA PMA P040020 and related documents to that PMA file. The FDA approved use for RESTOR was in part: “AcrySOF® ReSTOR® IOLs are indicated for the visual correction of aphakia secondary to removal of a cataractous lens in adult patients with and without presbyopia, who desire near, intermediate and distance vision with increased spectacle independence. The lens is intended to be placed in the capsular bag.” (Apr. 24, 2004, PMA PO40020, at Part 2, Summary of Safety and Effectiveness Data, ¶INDICATIONS).
Thus, the RESTOR is an example of an FDA approved IOL for near, intermediate and distance vision. The term “FDA approved IOL for near, intermediate and distance vision” refers to any IOL that has obtained FDA approval having an indicated use that provides for near, intermediate and distance vision, regardless of whether such IOL is actually being employed for such an approved use. The CRYSTALENS would also be an example of an FDA approved IOL for near, intermediate and distance vision. Moreover, the RESTOR and CRYSTALENS are examples of an FDA approved IOLs that reduce and/or eliminate the need for spectacles.
A schematic representation of the shape and general structure of an example of an accommodating IOL, along the lines of a CRYSTALENS, is provided in FIG. 8. This IOL has a lens structure 202, hinges 203 located adjacent to the lens structure 202 and haptics 204, which contact the lens capsule 201. The overall shape of this IOL would be non-geometric. As used herein the term “non-geometric shape” refers to shapes other than circles, ellipses, squares and rectangles. As used herein the term “geometric shape” refers to circles, ellipses, squares and rectangles.
The removal of the natural crystalline lens and replacement with a lens replacement material employ the use of a small initial incision or incisions in the limbal area of the eye, which is the transition area between the cornea and sclera. This initial incision is typically made with a small triangular blade that is pushed through the outer clear cornea of the eye. It is through this initial incision that other instruments for use in the removal and replacement of natural lens material are inserted. It is also through this incision that the natural lens material is removed from the eye and replacement lens material is inserted into the eye.
Once the initial incision has been made the removal of the opacified natural crystalline lens and replacement with a lens replacement material, such as an FDA approved IOL, presently employees a capsulorhexis and/or a capsulotomy. A capsulorhexis generally consists of the removal of a part of the anterior lens capsule and the creation of a hole or opening in the lens capsule, that results at least in part from a tearing action. A capsulotomy generally consists of a cutting of the lens capsule, without or with minimum tearing of the capsule. Thus, to remove the opacified natural lens material, the lens capsule is opened. There are several known techniques for performing a capsulorhexis and a capsulotomy.
One of these capsulorhexis techniques is a can opener approach. This approach uses a small bent needle to make small incisions around the anterior lens capsule to create an opening in the lens through which the lens could be removed. This technique quite often results in the opening in the lens capsule having ragged edges. Another of these techniques is a Continuous Curvilinear Capsulorhexis (CCC). CCC uses the same type of bent needle to begin the tear in the anterior lens capsule and then uses this needle and/or special forceps which are guided under the edge of the cut to tear a circular hole in the lens capsule. CCC, in comparison to the can opener approach, reduces the ragged edge around the opening in the lens that occurred with using the can opener technique. However CCC does not eliminate the formation of irregularities in the shape of the edge and the presence of these irregularities is dependent upon surgical skill and technique.
The use of a Fugo plasma blade to create the hole in the anterior capsule may also be used. This technique is referred to as a capsulotomy. The Fugo plasma blade is a hand held device and was originally utilized in dentistry. It is an electromagnetic device that focuses its energy on a blunt cutting filament. Information regarding the Fugo plasma blade can be found in FDA PMA K063468, K001498, K041019, and K050933 and U.S. Pat. No. 5,413,574.